Air-brake mechanism.



n. i. FRANKLIN.

Mn BRAKE MEcHAmsM. Armlehnen mio fia. 2, um.

1,274, 1 56. Patented July 30, 1918\` LME-7374" w fu/MLM UNTTED sTATEs PATENT OFFICE. f

.DAVID J. FRANKLIN, or COLUMBIA, SOUTH CAROLINA.

1R-BRAKE MncHANrsM.

To all whom it may concern:

Be it known that I, DAVID J; FRANKLIN, a citizen of the United States, residing at Columbia, in the county of Richland and State of South Carolina, have invented certain new and useful Improvements in Air- Brake Mechanisms, of which thefollowing is a specification. i

This invention relates to air brake mech@ anisms and the principal object thereof is to provide means for use with locomotive driver brake equipments for preventing an undesired application of the driver brakes. The invention liesin the formation, combination and arrangement of parts as will be herein 'described and claimed.

In the drawings, Figure lisa simplified diagrammaticalrepresentation, largelyy in section, of adistribut'ingvalve in common use on modern locomotives vand as manufactured bythe -Westinghouse Air Brake Company,of Pittsburgh, Pennsylvania, this valve being a portion of the wellknown Number 6 ET locomotive brake equipment of that company. Therel is shownin Fig. 1 in connection with this valve and therelated parts of the equipment the' new features which I employ to obtainbetter results and to overcome difficulties now eX- perienced inthe operation' of this equipment. Fig. 2 is a vertical sectional view of the leak-off valve which I employ and which is also shown in diagram in Fig. 1.

The operation of the distributing valve of this equipment is well known to those familiar with the air brake art and its various parts and numerous functionswill not Vbe goneinto at length herein. In order, however,'to fully explain my improvements the following brief.` description of a portionof itsworkings is given:

The pipe 1 leads from'the trainl 'line and' admits at. all times train linepressure into the chamber 2 on the-'one' sidev of the piston 3.- The partsare shown in release position, when pressureair is -fedthrough Vthe groove 4 around the piston 3 into the cavity 5, and charges the `reservoir 6. When aservice re-v duction is-madein lthe'train line pipe 1V the piston 3 moves to the right.' bringing the shoulder'7 ;of the'stem y8f against the valve 9 and then carrying it also lto the right until the port 10 thereof registers .with the port.

11 in the seat. ff Thev first movement of the pistonv 3 shifts the valve 12tothe right and uncovers the port 13, thereby admitting the Specification of Letters Patent.

Patented July 30, 19,18.

Application filed February 2, 1917. Serial No. 146,097.

air' from the cavity 5 and the reservoir 6 the communicating passageway 16 and pipe l 17 to the chamber 18 where it moves the piston 19 to the right. The movement of the piston 19 moves the valve 20 and admits main reservoir air from the pipe 21,'through the port 22 to the driver 4brake cylinders through the chamber 23 and pipe 24. At the same time thereservoir 27 has also beenV filled with air from the reservoir 6 to an equalized pressure through the ports'28 and the passages 29 and 30 and the pipe 31.

` The pipe 25 leads to the independent brake valve which, for automatic operation is-now in running position and -is through .this valve in communication withthe automatic brake valve, now in service position, where l chamber 18 and reservoir 27 areopen'to the "exhaust through the communicating ports, etc., and through the pipe 25, inde-V pendent brake. valve and the' connected vautomatic brake valve, both the brake valves being in'frunningl'rposition when the avuto-V matic brake valve opens this connectionto the atmosphere. With'the piston'3 andthe coperating` partsA in serviceV lapfposition, however, that'is,.w1th the valve 9rema1ning in its -full `service position but the piston f 3 retreated to 'the' left until the collar 32 of theV Stem"8 abutsthe right handend ofthe valve'9, the ,reservoir 27 and Vchamber 18v are blanked from the exhaust passage to the independent brake'valve. Andwhile the valve 12'has covered the port 13 andfthus blanked oil' communication Vbetween the chamber 5 `and the chamber 18, there'is the4 possibility 'of this valve leaking or of the narrow end bridge of theA valve9 leaking adjacentthe port 10. Leakagev at either place will apply the ibrakes'as the chamber 18 and reservoir 27 Yare now blankediby the valve'9 from the pipe 25. l

Itis of common knowledge thatone Orth other of these valves frequently leaks under i these circumstances and the result is thatV occasionally, when the parts have acciden-Y tally-shifted into. this. service lanposition by alealy tram llne or: the `jarof-ihfmov-y 2 ing locomotive, the locomotive driver brakes will be applied without the knowledge of the engineer', for while the automatic brake valve may be in running position and the pipe 25 consequently vented, yet the distributing valve parts have shifted without the knowledge ofthe engineer into this position where pressure can buildy up fronr leakage in the chamber 18.

It. is to render such a condition impossible with the parts so connected and the automatic brake valve in ruiming position that the present invention is directed and I shall new describe the new parts I employ and explain their operation in connection with this commercial air vbrake mechanism.

From the reservoir 27 I lead ay pipe 33, this pipe connecting with the pipe 25. In this pipe line I locate a cut-out cock 34 and my leak-olf valve 35. This valve 35 is so designed that vif a small amount of airis fedinto the reservoir 27 when the pipe 25 isA open to the atmosphere it willi leak olf through this valve. B'ut if a considerable volume of air is being admitted, as in servicethe valve 35l Vwillv be automatically shifted bythe built-up pressure, closing the leakofi"V port and holding the desired pressure until the cavity is exhausted, when the valve parts willagain shift into leak-olf position.

The cock 34 is provided so that the: valve 35 may be cut out of service in case of accident to it orv to preventv interfering with other desired operations of the air brake mechanism.

My leak-off-,valve 35 is constructed as follows:`

A casing 36 is provided with an opening 37 'in the one end thereof for connection with the pipe 33. This pipe isin fluid communication with the cavity 38 ofthe valve, the stem 39 of the piston 40`being channeled at 41` to provide fluid passageways through the guide42. The movable piston 40 lits within the cylindricalA cavity 43 and responds in movement to differences in pressure on its oppositesides. The=upper end of the casing 36 is closed by the head 44 `which is pierced to accommodate the pipe 33' and with air passageways 45 Vleading to the interior of the-.cavity 'and above-the'piston. It is.this end of' the valve that is in communication witfhthe reservoir 27, the'side opposite the pistonbeingl connected. tothe pipe 25' and therethrough to theatmosphere. A spring 46 extends frombeneath the piston 40, surrounding the stem 39thereof, to the upper end offthe guide 42which serves as an abutment for this spring.' The spring Vnormally holds the piston up against the stop 47 on the head44. As long as butsmallleakages occur the airwill leak offaround the piston 40Athrough therestricted channel 48.` But when larger volumes or airY are admitted, pressure will buildup in the cavity abovethe piston and overcoming the spring 46 will move the piston to close the lower end of the passageway 48, th'us preventing undesired leakage. Upon exhausting the air from the reservoir 27 the piston Will return to its normal position through the influence of the spring 46.

Thepiston 40 is made of a metal disk with an expanding leather packing 49 and a follower 50, this form of-piston being most suitable for my form of valve.

Thus the accidentalxleakage of air. into the chamber 27 will not now apply the driver brakes while an intentional applicationlwill not be interfered with.

Having thus described my invention, what I now claim is:

1. Inv an air brake mechanism, a distributing valve arrangement adapted to control the application of locomotivedriver brakes and embodying a casing, a movable piston therein, a feed groove around said piston, a reservoir adapted tobe charged through said feed' groove, a chamber adapted to be charged from said reservoir forl elfecting movement ofthe application valve, a valve actuated by the movements of: said piston and eontrollingithe admissionfof air to'said chamber, and a leak-offl valve connected` to said chamber and-adapted to allow the escape of air solong as it is admitted in small quantities, andto prevent the escape of air when admitted in larger quantities.

2. In an air brake mechanism,a distributing valve arrangement adapted to control the application of locomotive driver brakes and embodying a casing, a movable piston therein, a feedv groove around said piston, a= reservoir adapted to be charged through saidv feed groove, a chamber adapted to. be charged from said reservoir for effecting movement ofv the i application valve, a valve actuated Abyv the movements of said piston and cont-rollingv the admissionof air to said chamber, an independent brake valve, a pipe leading from thesaid distributing valve tothe independent brake valve and being there normally open tothe atmosphere, a second valve controlling communication between the said chamber and the pipe leading to theindependent brake valve, a second-I pipe line extending between said chamber andthe {i-rst said pipe around the said second' valve, and a leak-ofvalve in said second pipe line, adapted'to allow the escape ofair from the chamber so long as it is admitted in small' quantities,- and to prevent the escape of air when admitted in larger quantities.v Y

3. In an air brake` mechanism, a-distributing valve arrangement adapted' to control the application of locomotive driver` brakes and embodyinga casing', a movable piston therein, afeed-groove around said piston, a reservoirfadapted to-be charged through said feed groove, a chamber adapted to be charged from said reservoir for effecting movement of the application valve, a valve actuated b the movements of said piston and contro ling the admission of air to said chamber, and a leak-oil valve connected to said chamber and adapted to allow the escape of air so long as it is admitted in small quantities, and to prevent the escape of air when admitted in larger quantities, said leak-o` valve comprising a casing, an opening at one end thereof for connection with said chamber and an opening at the other end thereof leading to the atmosphere, a movable piston therein forming a closure across the cavity of the valve, a spring adapted to hold the piston in anormal extreme position toward the chamber-end of its cavity, a passageway of restricted` area around said piston when the latter is in its normal 20 position, the said piston being adapted to be shifted by the building up of pressure in the chamber to a position where the said passageway will be closed.

In testimony whereof I aix my signature 25 ,A

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. G. 

